> I’m able to see these packets without filter... Why can’t I see them
> with th filter?
>
> Some friend told me it's a libpcap problem. The libpcap version in
> my computer is 1.0.0-1 (almost the last one)
>
> What's going on??? I really don't understand.

A common cause of this seems to be when you have 802.1q VLAN tags
coming into the machine and being passed up into Wireshark. If this
is the case, you would need to use "vlan and <your filter>".